Industrial processes are employed in connection with producing numerous products that are utilized every day by consumers. For instance, everything from textiles to toothbrushes to automobiles to complex electronic devices is produced in industrial environments. To effectuate production of such items, complex and oftentimes dangerous equipment must be employed. For example, to create an automobile door, sheet metal must be cut in a desired shape by large cutting devices. Without adequate safety mechanisms, one or more individuals may become seriously injured and/or disfigured by accidentally placing a body part in an improper place at an inopportune time. Thus, many industrial devices are associated with safety mechanisms that cause such devices to automatically shut down when an individual or object is detected in an improper position.
One example of a safety device that is commonly employed in industrial environments is a safety light curtain. Safety light curtains are utilized to ensure that objects of threshold sizes do not come within a certain distance of particular portions of machinery. More specifically, a plurality of light emitters are aligned with a plurality of light detectors such that multiple beams of light are emitted in parallel to one another by the emitters and received by respective detectors. The detectors can be coupled to a device that is employed in connection with analyzing the light signals (the beams of light). In a detailed example, the detectors can be sequentially enabled by a shift register, and the received light signal can be analyzed in sequence by a microprocessor, which determines status of each light beam (e.g., whether a certain light beam is impeded).
If, upon analyzing the received signal, a determination is made that one or more beams of light has been impeded (such that light emitted from an emitter does not reach a corresponding detector), a microcontroller can communicate with output devices that are coupled to a controlling element to shut down a machine associated with the safety light curtain. Thereafter the machine can be manually restarted upon the beams being unimpeded. As can be surmised from the above, safety light curtains have saved numerous individuals from serious injury as well as increased useful life of machines (by protecting such machines from foreign objects in sensitive areas).
Today's safety light curtains, however, are not without deficiencies. In particular, conventional safety light curtains can be complex in nature, as they must include multiple emitters and detectors (one each for a beam of light). In larger safety light curtains, a significant number of emitters and detectors may be required, thus resulting in significant cost and reliability concerns for such light curtains. Furthermore, in environments where explosion is possible, all electrical devices (e.g., each emitter and detector) must be enclosed in explosion-resistant housing. Again, with larger light curtains, housing each emitter and each detector with explosion-resistant material can be quite costly.